Multiple-roll rolling mill for exchangeable work rolls of substantially varying diameter



May 9, 1967 K. J. NEUMANN MULTIPLE-ROLL ROLLING MILL FOR EXCHANGEABLEWORK ROLLS OF SUBSTANTIALLY VARYING DIAMETER 2 Sheets-Sheet 1 Filed Nov.z, 1964 mm a 5 am R mm R w May-9., 1967 K. J. NEUMANN 3,313,131

MULTIPLE-ROLL ROLLING MILL FOR EXCHANGEABLE WORK ROLLS OF SUBSTANTIALLYVARYING DIAMETER Filed Nov. 2, 1964 2 Sheets-Sheet 2 Fig. 2

United States Patent 3,318,131 MULTIPLE-ROLL ROLLING MlLL FOR EX-CHANGEABLE WORK ROLLS 0F SUBSTAN- TIALL'Y VARYING DIAMETER Karl JosefNeumann, St. Ingbert, Saar, Germany, as-

signor to Verwaltangsgesellschaft Mueller & Neumann ofieneHandelsgesellschaft, St. Inghert, Saar, Germany Filed Nov. 2, 1964, Ser.No. 408,427 Claims priority, application Germany, Oct. 31, 1963, V24,787 5 Claims. (Cl. 72-243) The invention relates to a cold rollingmill having more than four rolls, especially to a so-calledmultiple-roll rolling mill for rolling thin sheets or strips. It isknown that the thinnest strip thickness which may be rolled on a coldrolling mill determines the diameter of the working rolls. Thick workingrolls of a four-high rolling mill allow substantial pass reductions butroll only down to a strip thickness at which the roller flattening, dueto the solidification of the strip, becomes greater so that even with anincreased rolling pressure no further noticeable reductions can beobtained. In the case the strip is to be rolled even thinner, or in thecase where a hard material is worked, one must use a multiple-rollrolling mill having small diameter working rolls.

It is therefore an object of this invention to provide a multiple-rollrolling mill which has the advantage of a four-high rolling mill withthick work rolls, that is to say large pass reductions at the beginningof the rolling operation of a strip are combined with the advantages ofa multiple roll rolling mill having thin or small diameter workingrolls, namely the possibility of a further rolling also of hard stripsdown to the smallest strip thicknesses.

It is a further object of the invention to provide a multiple-rollrolling mill for inserting working rolls of substantially varyingdiameter.

Multiple-roll rolling mills are already known in which instead of atwo-high or four-high roll set also roll sets having thin work rolls arebuilt-in and in which the thick work rolls are supported on the sides bya series of additional backing rolls. While in the case of a four-highoperation the thick work rolls are driven it is necessary to change thedrive to the backing rolls upon a transition to thin work rolls.

It is a further object of the invention to maintain the coupling of thedriving spindles with the driven rolls in the case where the rollingoperation is changed from thin or small diameter working rolls to thickor large diameter working rolls. By thick working rolls are to be under:stood those which have a diameter comparable to the usual Working rolldiameters employed in four-high rolling mills.

The objects of the invention are to be accomplished with the smallestpossible number of rolls. The best known multiple-roll rolling millpresently has twenty rolls.

Contrary to this the rolling mill according to the invention shouldcomprise not more than ten rolls.

The invention is based on a multiple-roll rolling mill having on bothsides of the rolling gap roll sets comprising each an equal amount ofrolls, and each set consisting of a working roll, two drivenintermediate rolls and two backing rolls for absorbing the forcesreceived by the intermediate rolls, wherein the intermediate rolls aremounted in chocks which are guided radially of the axial center lines ofthe backing rolls. Based on the knowledge that in the case of such aten-roll rolling mill whose rolls are disposed in an X-arrangement asdisclosed in British Specification 870,777 the varying forces resultingfrom the rolling pressure, the driving moment and the strip tension,which act on the intermediate rolls and depending on the diameter of theworking rolls, must be taken up without additional intermediate orbacking rolls by the inclined guides of the intermediate roll chocks, itis the purpose of the invention to eliminate the force componentsresulting from the rolling pressure and having the effect of a bearingpressure in the intermediate roll chocks as it is the case in afour-high rolling mill. This is to be expected when in each working rolldiameter the axis center lines of the intermediate rolls each areadjusted to the inclined connection lines between the axis center linesof the associated working roll and of the backing roll against which theintermediate roll bears. This adjustment is obtained according to theinvention in that the guides for the chocks of the driven intermediaterolls consist of pivot elements which are movable around the axis centerlines of these backing rolls both symmetrically in that the horizontaldistance of the intermediate rolls from each other is adjustable bymeans of a displacing device which engages directly or indirectly at thepivot elements in the same pivot direction to set the axial center linesof the intermediate rolls unsymmetrically out of alignment with theconnection lines between the working roll and the axial center of thebacking rolls.

In the simplest embodiment of a rolling mill according to the inventionthe pivot element of each backing roll may be displaced individually orin pairs of superimposed backing rolls together. In this manner one isable to adjust the pivot elements of a pair of intermediate rolls whichdrive a work roll unsymmetrically to the vertical plane running throughthe axis center lines of the work rolls in order to produce in theintermediate roll chocks a force component resulting from rollingpressure directed against the bearing pressure in the intermediate rollchocks, which equals the resulting bearing pressure derived from thedriving rotation moment and the strip tension which engages at the twodriven intermediate rolls in the same horizontal direction. This isobtained by the individual displacement of the axis center lines of theintermediate rolls laterally of and out of alignment with the mentionedinclined connection line between the working roll center and the backingroll center, called hereafter articulated position.

In this manner it is obtained that from the intermediate rolls onlyforces directed radially to the backing roll axis center lines aretransferred and that the forces which exert on the pivot elements arotating moment to be absorbed by the displacing device disappear.

From a construction view point it is advantageous to make the pivotelements adjustable relative to each other symmetrically to the verticalplane which runs through the center lines of the Working rolls so thatrotating moments are constantly effective at the pivot elements wherebythe adjusting parts remain loaded. In order to displace also in the caseof a symmetrical displacement of the intermediate rolls opposite to eachother, which is to be carried out upon a transistion to another workingroll diameter, the intermediate roll axis center lines laterally awayfrom the connection lines between the working roll and backing roll axiscenter lines for setting the articulated position, whereby the forcesarising from the rolling pressure at the intermediate rolls are directedagainst the forces resulting from the driving rotation moment and thestrip tension, the invention provides that the pivot elements are alsopivotable in a displacement in the same direction of rotation.

As the forces resulting from the driving moment and the strip tensionwhich are effective at the intermediate rolls change their directionwith each reversing pass, the invention purposes that the pivot elementsmay be switched over with each reversing pass in the same pivotdirection, namely between two predetermined pivot positions which aresymmetrical to the inclined connection line of the axis center lines ofthe associated backing rolls and working rolls.

Other objects and advantages will be apparent from the specification andclaims and from the accompanying drawings which illustrate an embodimentof the invention.

FIGURE 1 shows the lower roll set of a ten-roll rolling mill with anadjusting device for the pivot elements, the roll set in side view andthe displaying device in crosssection.

FIGURE 2, a cross-section along line II-II in FIG- URE 1 showing partsof the roll assembly with a pivot element and FIGURE 3, a roll asemblyincluding the composition of forces.

As may be seen with reference to FIGURE 1, the roll set consists of aworking roll 1, two intermediate rolls 2, 3 engaging the working roll,and of two large backing rolls 4 and 5. The intermediate rolls 2, 3 aredriven by suitable means (not shown). For setting the position of theintermediate rolls 2, 3 they are mounted in chocks 6, 7 which are guidedby bolts 8, 9 in cross bores 10, 11 of the backing roll shaft 4a, aradially to the axis center line 4b, 5b of the backing rolls, so thatthe intermediate rolls bear always against the backing rolls even aftersome wear. The pivot elements 12, 13 are secured on the backing rollshafts 4a, 5a at both ends, for example by a shrunk-fit, and these pivotelements extend the guide bores 10, 11 for the bolts 8, 9.

The horizontal distance between the intermediate rolls may be varied inopposite direction to each other with respect to the vertical centerplane 14 by a symmetrical pivoting of the pivot elements 12, 13. Thisdisplacement is carried out when instead of the thin work roll 1, whichin the embodiment shown, has a diameter of 80 mm., a thick working roll15 shown in dot-and-dash lines and having a diameter of 250 mm. is to beinserted. The intermediate rolls are then moved into the positions 2a,3a, shown in dot-and-dash lines, in which positions the axis centerlines of the intermediate rolls are located on the inclined connectionlines 16, 17 between the axis center lines of the working roll 15 and onthe axis center lines 4b, 5b of the backing rolls 4, 5. This position ofthe intermediate rolls in alignment with the axis center lines of theadjacent rolls Will be called hereafter the neutral position.

In inserting thick work rollers the roll sets of the rolling mill are tobe separated from each other a corresponding amount by a screw-downdevice (not shown). In the case of a ten-roll rolling mill thescrew-down distance is to be so measured that instead of thick workingrolls 51 for rolling down a strip thin working rolls 1 of less than halfthe diameter of the thickest working rolls 15 may be inserted.

The backing rolls 4 and 5 consist of stationary shafts 4a, 5a withindividual roller bearing rings "19 mounted in spaced relationship. Theshafts 4a, 5a are mounted on both sides of the bearing rings 19 incommon frames 18. By means of this known type of backing rollconstruction having thick shafts it is possible, according to theinvention, to provide the displacement devices for pivoting and settingthe pivot elements 12, 13 only on one side of the roll sets, as thepivot elements on the other side of the torsion resisting backing rollshafts 4a, 5a are also coupled to them non-rotatably and follow therotation.

In order to adjust the pivot movements of the pivot elements 12, 13moving in opposite directions or in the same directions in a simplemanner, the invention provides for each roll set displacement deviceswhich comprise displacement elements which may be driven in oppositedirections or in the same directions and which may be fixed in position.

The drawing shows a displacement device which has the advantage of notrequiring any linkage parts and which may be so tensioned that duringthe rolling operation no play can be effective in the displacementparts. For displacing each pivot element 12 or 13 of a roll set asetting cylinder 21, 22 respectively is provided which may be displacedin the axial direction, these setting cylinders being guided in theembodiment illustrated in a common guide cylinder 20. The settingcylinders 21, 22 each receive a pair of pistons having pistons 23, 24,and 25, 26 which may be moved back and forth hydraulically in pairs inthe same direction. These piston sets engage on each side a lever arm12a or 13a of the pivot elements 12 and 13. Between the lever arms andthe piston pairs an articulated connection is provided at which thelever arms carry ball-shaped recesses 1212 or 1312 and the pistons 23 to2d ball-shaped pressure parts 27. The pistons 23, 24 may be put underpressure over hydraulic conduits 28 and 29 in the opposite direction byhydraulic pressure so that the joints at the lever arms 12a and 13a arealways without play. In the illustrated neutral position of theintermediate rolls 2 on the connection line between the axis center lineof the work roll 1 as well as of the backing roll 4 both pistons 23 and24 have a small axial play relative to the cylinder covers 2111 of theircommon cylinders 21. This axial play makes it possible to displace byalternate admission of pressure against the one or the other piston 23or 24 through conduits 28, 29 the lever arm 12a of the pivot element 12and thus also the intermediate roll 2 toward the one or the other sidefrom the neutral position. The same hydraulic displacement in the samedirection is also provided by the pistons 25, 26, which are displaceableover hydraulic conduits 30, 31 through the axial play s relative totheir stationary cylinder 22.

- movements of cylinders 21, 22 inwardly may be carried out, when thepressure in pressure chamber 33 is cut off. After each displacement ofthe cylinders 21, 22 over the stop spindles 34, 35 pressure is againgenerated .in pressure chamber 33 in order to make the mechanism of thedisplacement device free of play. In order to fix the stop spindles 34,35 hand wheels 38, 39 are provided in order to counter the threadconnection.

It is to be understood that a displacement device for pivot elements 12,13, described herebefore, must also be provided at the upper roll set ofthe ten-roll rolling mill (not illustrated).

The operation of the ten-roll rolling mill of the invention as well asthe possible working processes and their operation will now be explainedin greater detail:

The setting 0 the intermediate rolls In FIGURE 1 the intermediate rolls2, 3 for the bearing of the very thin working roll 1 are set to aminimum distance from each other. Before inserting a thicker workingroll 15 it is necessary to swing the pivot elements 12, 13 in oppositedirections outwardly to such an extent that the intermediate rolls 2, 3move into the position 2a, 3a shown in dot-and-dash lines, in whichsymmetrical position their axis center lines lie on the connection lines16 and 17 between the axis center lines of the Working roll 15 and thebacking rolls 4 and 5. The axis center lines of the intermediate rollsmove on arcs 40 and 41 during this displacement. The setting position isreleased in that first the counter hand wheels 33, 39 are loosened andthe cylinders 21, 22 are brought closer to each other 5 by threading inthe stop spindles 34, 35. During this operation the pressure in thechamber 33 must be let off temporarily. It is to be understood thatinstead of the manual operation also a motor drive may be provided forthe stop spindles 34, 35. The correct adjustment of the cylinders 21, 22corresponds to the diameter of the new working roll 15 and may bedetermined from a dial (not shown).

The setting the intermediate rolls to the articulated position Beforethe setting of the pass reduction of the first pass with inserted stripby the screw-down device acting on the upper roller set (not shown) fora rolling direction as shown in FIGURE 3 going from left to right thepressure lines 28 and 31 are connected with the pressure source, and thepressure conduits 29, 30 are switched in reverse. Thereby the pistonpairs 23, 24- and 25, 26 are displaced toward the right by their axialplay s, so that the intermediate rolls 2 and 3 move into the full linearticulated position according to FIGURE 3. In this articulated positionthe intermediate rolls 2 and 3 are displaced with respect to theconnection lines 16, 17 of the neutral position opposite to the rollingdirection. This articulated position of the driven intermediate rolls 2,3 reduces the forces which are produced from the driving rotatingmovement and the strip tension and which act as rotating moment on thepivot elements 12, 13. According to the invention the displacement ofthe axis center lines of the intermediate rolls 2, 3 is switched overbeyond the neutral position opposite to the new rolling direction withrespect to the changing direction of the forces which occurs during thereversing before each reversing and before each pass reduction by thescrewdown device. The new position of the intermediate rolls is shown inFIG. 3 in dash-and-dot lines. For this position the pressure conduits29, 30 are simply connected to the pressure source and the pressureconduits 28, 31 are switched to reversing. Upon a change-over of thearticulated position the piston pairs 23, 24 and 25, 26 therefore movein the same direction, in each case double the amount of their axialplay s. As each piston abuts alternately against the cylinder covers 21adepending on the articulated position and as thehydraulic pressure bearson the oppositely located piston the joints between the pistons 23 to 26and the pivot elements 12, 13 or their lever arms 12a, 13a remainloaded.

In order to determine the end positions of the articulated positon onemust investigate the forces which arise in the system. In the force planaccording to FIGURE 3 the intermediate rolls 2, 3 are displaced for therolling direction from left to right opposite to the rolling directionrelative to the connection line 16, 17 of the neutral position. Therolling force P is divided into the unequal components P and P which aredirected to the axis center lines of the intermediate rolls 2, 3 andinto two components which are directed perpendicularly thereto, whichare not of interest in this connection. With reference to theintermediate rolls the components P and P may again be divided intoforces P or P directed to the axis center lines 4b, 5b of the backingrolls and into forces P or P which are perpendicular thereto. It isthese forces which exert-' over the checks 6, 7 of the intermediaterolls 2, 3 as hearing pressure a rotation moment on the pivot elements12, 13 where no equal oppositely directed forces oppose them.

The opposiing forces are derived from the peripheral forces which engageat the driven intermediate rolls, namely the forces P and P resultingfrom the driving rotation moment and the strip tension as well as theforces P and P resulting from the roll friction moments between theintermediate rolls and the backing rolls as well as from their rollerbearings. By parallel displacement of these forces P and P identifiedhereafter as buckling forces result by subtraction of the smaller P-forces from the always larger P -forces counterforces P and P which aredirected opposite to the buckling forces P and P In the force planaccording to FIG. 3 the conditions are assumed to be such that thebuckling force P for the intermediate rolls 3 is equal to thecounterforce P Therefore no rotation moment which would have to be takenup by the displacement device is exerted on the pivot element 13.

As for the other intermediate roll 2 the counterforce P is equal to Pbut the buckling force P is smaller due to the outwardly directedarticulated position (P smaller than P A remaining force is effective atthe intermediate roll 2 which tends to drive the intermediate roll 2inwardly. This remaining force is absorbed over the piston 23 by thepressure means when the pressure conduit 28 is closed.

As embodiment of this working process it is assumed that a strip is tobe rolled with a constant rolling pres sure of P equals 1000 t. Thedriving rotation moment is assumed to be 2830' mkg. at the first pass,the strip tension 12 t. It is further assumed that the forces P and Presulting from the driving rotation moment and the strip tension, whichalways act against the rolling direction on the intermediate rolls 2, 3and are calculated for the first pass as 16,200 kg. becomes smaller frompass to pass, namely in the ratio 4:1, calculated from the first to thelast pass. At the last pass the forces P and P are therefore 4050 kg.The end positions of the articulated positions of the intermediate rollsare now so chosen that the buckling forces P and P amount on the averageto about two and a half times the smallest P -forces of 4050 kg., thus10,200 kg. If six passes are assumed and the P -forces decrease from16,200 kg. linearly to 4050 kg. the following table is obtained:

PAR= AR, a= aZ AR- PAnPa,

It will be observed that the remaining forces which would engage at theaxis center lines of the intermediate rolls 2, 3 are at a maximum at thefirst and last pass and tend due to their opposite directions in themiddle passes, to a minimum. By the working process described themaximum remaining forces which arise are kept small.

What is claimed is:

1. Multiple-roll rolling mill including two sets of rolls on both sidesof the rolling gap; each roll set comprising a work roll of smalldiameter, two driven, horizontally spaced intermediate rolls engagingsaid work roll and two horizontally spaced backing rolls arranged at afixed distance from one another for engaging each one of said twointermediate rolls; said intermediate rolls being supported in checkscarried on guide means mounted for adjustment radially of the axialcenter lines of said backing rolls, said guide means including pivotelements movable about the axial center lines of said backing rolls; adiplacement device for moving said pivot elements both symmetrically tochange the horizontal distance of said intermediate rolls from eachother for adapting said distance to the actual working roll diameter,and in the same pivot direction to set the axial center lines of saidintermediate rolls unsymmetrically and out of alignment with theconnection lines between the axial center of the working roll and thebacking rolls. to absorb the components force resulting from the rollingpressure, the driving rotation moment and the strip tension, taken up bysaid pivot elements.

2. Multiple-roll rolling mill according to claim 1 in which the amountof horizontal spacing of said intermediate rolls is adapted forinserting selectively thick and thin work rolls for cold Workingoperation, each said thick Work roll having a diameter more than twicethe diameter of each said thin Work roll.

3. Multiple-roll rolling mill according to claim 2 in which saiddisplacing device for one pivot element consists of a setting cylindermovable in an axial direction containing two pistons hydraulicallyreciprocable in the same direction, said pistons engaging in pairs alever arm of said one pivot element on opposite sides.

4. Multiple-roll rolling mill according to claim 3 in which the settingcylinder is guided like a piston in a stationary guide cylinder whichforms on one side of the setting cylinder a pressure chamber forintroducing pressure fluid means whose pressure loads a mechanicallyoperated setting device at the other side of the setting cylinder.

5. Multiple-roll rolling mill according to claim 4 in which said settingcylinders for moving said pivot elements of a roll set are disposed in acommon guide cylinder and form between them said pressure chamber forloading adjustable stop spindles which act from the outside against saidsetting cylinders.

References Cited by the Examiner UNITED STATES PATENTS CHARLES W.LANHAM, Primary Examiner.

E. M. COMES, Assistant Examiner.

1. MULTIPLE-ROLL ROLLING MILL INCLUDING TWO SETS OF ROLLS ON BOTH SIDESOF THE ROLLING GAP; EACH ROLL SET COMPRISING A WORK ROLL OF SMALLDIAMETER, TWO DRIVEN, HORIZONTALLY SPACED INTERMEDIATE ROLLS ENGAGINGSAID WORK ROLL AND TWO HORIZONTALLY SPACED BACKING ROLLS ARRANGED AT AFIXED DISTANCE FROM ONE ANOTHER FOR ENGAGING EACH ONE OF SAID TWOINTERMEDIATE ROLLS; SAID INTERMEDIATE ROLLS BEING SUPPORTED IN CHOCKSCARRIED ON GUIDE MEANS MOUNTED FOR ADJUSTMENT RADIALLY OF THE AXIALCENTER LINES OF SAID BACKING ROLLS, SAID GUIDE MEANS INCLUDING PIVOTELEMENTS MOVABLE ABOUT THE AXIAL CENTER LINES OF SAID BACKING ROLLS; ADISPLACEMENT DEVICE FOR MOVING SAID PIVOT ELEMENTS BOTH SYMMETRICALLY TOCHANGE THE HORIZONTAL DISTANCE OF SAID INTERMEDIATE ROLLS FROM EACHOTHER FOR ADAPTING SAID DISTANCE TO THE ACTUAL WORKING ROLL DIAMETER,AND IN THE SAME PIVOT DIRECTION TO SET THE AXIAL CENTER LINES OF SAIDINTERMEDIATE ROLLS UNSYMMETRICALLY AND OUT OF ALIGNMENT WITH THECONNECTION LINES BETWEEN THE AXIAL CENTER OF THE WORKING ROLL AND THEBACKING ROLLS TO ABSORB THE COMPONENTS FORCE RESULTING FROM THE ROLLINGPRESSURE, THE DRIVING ROTATION MOMENT AND THE STRIP TENSION, TAKEN UP BYSAID PIVOT ELEMENTS.